Sucker rod coupling



June 3, 1 J. J. FITZPATRICK SUCKER ROD COUPLING Filed Jan. 19, 1939Patented June 3, 1941 UNITED STATES PATENT OFFICE lSUCKER ROD COUPLINGJeremiah J. Fitzpatrick, Oklahoma City, Okla.

Application January 19, 1939, Serial No. 251,731

6 Claims.

My invention relates to couplings for pump rod sections, and is designedfor use particularly with sucker rod strings in deep wells, such as oilwells.

The prime object of the invention is the provision of a rod couplingwhich not only connects adjacent ends of rod sections, but also acts tocut accumulated paraffin from the walls of a string of productiontubing.

Another object is to provide a combination rod coupling and paraffinscraper so designed that a minimum amount of fatigue, usually due towall friction. is exerted upon the coupling portion of the device, andthe greater amount of the fatigue is borne by the paraflin scrapingelement, the tendency of the coupling proper to become crystallized andto part under strain, thus being reduced to a minimum.

A further object of the device is the provision of a combinationcoupling and paraiiin scraper in which the scraping element, whichreceives the major portion of wear, is separate from the rod couplingelement, and may therefore be formed of a metal particularly treated tostand the wear, while the coupling element proper may scraper in whichthe scraping element is replaceable when worn.

A further object is the provision of a combination rod coupling andparaffin scraper which also functions as a rod guide.

Other objects of the invention will be apparent by reference to theaccompanying one-sheet drawing wherein like characters of referencedesignate like parts in all of the figures.

In the drawing:

Figure 1 is a perspective view of the rod coupling element of the deviceper se, the scraping element having been removed;

Figure 2 is an elevational view of the scraping element;

Figure 3 is a view similar to Figure 1 with the scraping elementinstalled upon the coupling element.

Figure 4 is an elevational view of a box and box embodiment of thecomplete device;

Figures 5 and 6 are transverse sectional views taken substantially alongthe lines 55 and 66 respectively of Figure 4; and,

Figure 7 is a detail of one of a plurality of outstanding lugs which arecarried by the coupling element.

One practical embodiment of the invention is illustrated in the drawingwherein the reference numeral l indicates as a whole a rod connectingelement consisting substantially of two alined cylindrical rod receivingmembers 2 and 3 both threaded to receive adjacent ends of sucker rodsections, not shown. The members 2 and 3 may be constructed of the pinand box type as shown in Figures 1 and 3, or the device may beconstructed in the box and box type and have two of the boxes 3 asillustrated in Figure 4. The members 2 and 3, or 3 and 3 as the case maybe, are rigidly connected to each other by a plurality of integral vanesor ribs 4 which extend radially outward from a common center, whichcenter is in alinement with the longitudinal axes of the members 2 and3, or 3 and 3. The outer edges of the vanes 4 project outwardly beyondthe exterior surface of the members 2 and 3 or 3 and 3, and their endsare each bevelled both laterally and longitudinally to form convergingfaces 5 and 6 separated by a knife-like parafiin cutting edge I. Thefaces 5-6 and the edge I meet at the exterior surface of the members.Intermediate their ends, each of the ribs 4 are provided with elongatednotches 8 which are in radial alinement with each other for receiving atubular paraffin scraping element 9, best seen in Figure 2. Both endwalls H) of each notch 8 are bevelled, and both ends of the scrapingelement are similarly bevelled as indicated at H to fit the bevelledends of the notches 8.

The scraping element 9 is generally tubular in form and has alongitudinal line of severance I! along which it has been cut. Thelongitudinal cut 12 allows the element to be sprung open sufficiently topermit its being passed over the outer edges of the ribs 4 and into thenotches 8 of the element I. In installing the scraping element upon thecoupling element, the cut I2 is placed along one of the ribs 4, and thecut is then closed by Welding and when so installed, the periphery ofthe element 9 lies flush with the outer edges of the ribs 4. Each end ofthe element 9 is provided with notches I3 which occur between the ribs4, when the element is properly positioned, and the bevelled portions llfollow the entire contour of 4, and which are located one each betweenad- Jacent ribs 4. Both ends of the lugs I4 are shaped similarly to thatof theends of the ribs has above described, having bevelled side facesI5I6, and an intermediate knife-edge I1.

Operation The couplings are installed at desired intervals throughoutthe sucker rod string, and therefore function with each stroke ofthe'pump to keep the production tubing free of paraflin at the points ofinstallation, foria distance equal to the length of the rod stroke. Theparaffin along other portions of the tubing may be removed by raisingthe rod string a distance equal substantially to the interval betweenthe installations.

It may readily be seen that the notches I3 prevent any possibility ofthe sleeve portion of the device fowling with the spaces betweensections of production tubing, since no laterally ex-. tending surfaceis presented to the ends of the tubing sections. The ends of the ribs 4and lugs I4 being bevelled act to prevent their hanging between thetubing sections.

Operative tests have shown that a much better result is obtained byforming the device so that the leading ends of the ribs and lugs, oractually the cutting edges I and I1, precede the cutting edges of thesleeve 9 in contacting the parafiin, than could be obtained by utilizingonly the cutting edge of the sleeve for removing the paraflin. Thecutting edges 1 and I 1 act as plows for loosening the paraflin, and thefollowing cutting edges of the sleeve can then better remove theloosened parafiin.

The lugs I4 perform a further function in helping to protect the sleeveagainst collapse due to side thrust occasioned by the well being crookedand the tool therefore being dragged violently against a side Wall ofthe tubing. This feature might at first glance seem trivial, but testshave shown thatioads of 18,500 pounds are common in deep pumping wells,and that at the time the rods are reversed in motion during the pumpingstroke, a 5000 pound blow is usually delivered. This blow together withthe load present upon the rods could well collapse a sleeve typeparaifln scraper unless the blow against the tubing wall is distributedin the coupling over a considerable length of span. The end portions ofthe ribs 4- and the lugs I4 together act to receive a portionof thisshock, and thereby make it possible to provide a sleeve type scraperwith adequatefiuid passage through the sleeve and between the ribs. Thelugs I4 prevent the sleeve from being flattened between the ribs 4, whenthe blow is delivered.

Should the sleeve 9 become worn or damaged, it may easily be cut loosefrom the element or body I and a new one welded in place.

It is pointed out that not only does the present device act to couplerod sections and remove fparaifin, but it also functions as a rod guidefor preventing wear between the production tubing and the sucker rodstring. The construction of the coupling-element I and the scrapingelementof two difierent metals permits the sleeve to be made of a metalwhich will glaze under friction with the tubing and will not becomerough or gauld. The distance from end to end of the ribs is such thatconsiderable bearing surface is presented against the tubing.

I claim:

1. A sucker rod coupling, including: upper and lower rod connectingmembers having their axes aligned; longitudinally extending vanes, theirends connecting the members and their adjacent edge portions integrallyconnecting each other in substantial alignment with the axes of said rodconnecting members, said vanes extending radially outward from theirpoint of interconnection past the peripheries of the rod connectingmembers, both ends or each vane being bevelled inwardly to the peripheryof one of said rod connecting members and also being bevelled laterallyto'form sharp outwardly presented paraflin cutting edges, each vanehaving a longitudinally extending indenture in its outer edge; and, av

tubular sleeve seated around the vanes within said indentures, itsperiphery lying flush with the outer edges of the vanes, said sleevehaving notches in its ends which are located between the vanes andwhich. act to prevent lodgement of the device in interstices of tubingjoints, said sleeve ends being bevelled inwardly to form continuousparaflin cutting edges.

2. A sucker rod coupling, including: upper and lower rod connectingmembers having their axes aligned: longitudinally extending vanes, theirends connecting the members and their adjacent edge portions integrallyconnecting each other in substantial alignment with the axes of said rodconnecting members, said vanes extending radially outward fromtheirpoint of interconnection past the peripheries of the rod connectingmembers, both ends of each vane being bevelled inwardly to the peripheryof one of said rod con- I necting members and also being bevelledlaterally to form sharp outwardly presented paraifin cutting edges, eachvane having a longitudinally extending indenture in ,its outer edge;and, a re movable tubular sleeve seated around the vanes within saidindentures, its periphery lyingiiush with the outer edges of the vanes,said sleeve having notches in its ends which are located between thevanes and which act to prevent lodgement of the device in interstices oftubing joints, said sleeve ends being bevelled inwardly to formcontinuous parafiin cutting edges.

3. A sucker rod coupling, including: upper and lower rod connectingmembers having their axes 'aligned; longitudinally extending vanes,their ends connecting the members and their adjacent edge portionsintegrally connecting each other in substantial alignment with the axesof said rod connecting members, said vanes extending radially outwardfrom their point of interconnection past the peripheries of the rodconnecting members, both ends of each) vane being bevelled inwardly tothe periphery of one of said 'rod connecting membersand also beingbevelled laterally to form sharp outwardly presented parafiin cuttingedges, each vane having a longitudinally extending-indenture in itsouter edge;

a tubular sleeve seated around the' vanes Within said indentures, itsperiphery lying flush with the outer edges of the vanes, said sleevehaving notches in its ends which are located between the vanes and whichact to prevent lodgement of the device in interstices of tubing joints,said sleeve ends being bevelledinwardly to form continuous parafllncutting edges; and, radially spaced outwardly projecting lugs carried bythe rod connecting members for contacting the inner wall of a tubingstring, both ends of each lug being bevelled inwardly to the peripheryof its supporting rod connecting member and also being bevelledlaterally to form sharp outwardly presented paraffin cutting edges.

4. A sucker rod coupling, including: upper and lower rod connectingmembers having their axes aligned; longitudinally extending vanes, theirends connecting the members and their adjacent edge portions integrallyconnecting each other in substantial alignment with the axes of said rodconnecting members, said vanes extending radially outward from theirpoint of interconnection past the peripheries of the rod connectingmembers, both ends of each vane being bevelled inwardly to the peripheryof one of said rod connecting members and also being bevelled lateral:ly to form sharp outwardly presented paraflin cutting edges, each vanehaving a, longitudinally extending indenture in its outer edge; aremovable tubular sleeve seated around the vanes within said indentures,its periphery lying flush with the outer edges of the vanes, said sleevehaving notches in its ends which are located between the vanes and whichact to prevent lodgement of the device in interstices of tubing joints,said sleeve ends being bevelled inwardly to form continuous parafiincutting edges; and, radially spaced outwardly projecting lugs carried bythe rod connectingmembers for contacting the inner wall of a tubingstring, both ends of each lug being bevelled inwardly to the peripheryof its supporting rod connecting member and also being bevelledlaterally to form sharp outwardly presented parafiln cutting edges.

5. Organization as described in claim 2 in which the sleeve is severedalong a single longitudinal line of cleavage so that it may be expandedto pass over the ends of the varies in reaching its position in thenotches therein.

6. Organization as described in claim 2 in which the sleeve is severedalong a single longitudinal line of cleavage so that it may be expandedto pass over the ends of the vanes in reaching its position in thenotches therein, and

means for connecting the edges of said sleeve along the line ofcleavage.

JEREMIAH J. FI'IZPA'I'RICK.

